>The workflow for both the top vs. bottom (or bottom vs. top) are
>identical.
So if you had to do 5 boards you would have to do the following steps
5 times, once for each board;
----------------------------------------------
-- Combine in Photoshop the artwork for top, bottom, and silkscreen.
Printthis centered onto ordinary bond paper. Trim and tape a piece of
transferpaper over the artwork, and run it through the printer again,
this time printing onto the just-right sized piece of transfer paper.
Separate the three images.
-- Print the drill guide and legend. Stick it to the board with spray
mount adhesive.
-- Drill and debur the board. There are three unconnected vias in the
board corners for alignment pins.
-- Pierce the alignment vias on the top artwork; place the pins in the
board; place the top artwork over the pins. Visually confirm
alignment, and tape in place. Black toner should occlude all holes.
------------------------------------------------
Do you know how double sided boards are done using photoetching?
--- In
Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...>
wrote:
>
> ----- Original Message -----
> From: "derekhawkins" <derekhawkins@y...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Wednesday, November 16, 2005 3:18 PM
> Subject: [Homebrew_PCBs] Re: A $500.00 "UV" non-trivial exposure
box.....
>
>
> > >For production runs of one or very few, the case for
> >>100% of "HOMEBREW PCBs", you'll have to explain as though to a
young
> >>child the advantages that offset the cost and complexity of photo
> >>exposure.
> >
> > We'll get into the quality of the finished product later. Have
you ever
> > done a double sided board using TT? If yes then explain the TT
process.
>
> The workflow for both the top vs. bottom (or bottom vs. top) are
identical.
>
> -- Combine in Photoshop the artwork for top, bottom, and
silkscreen. Print
> this centered onto ordinary bond paper. Trim and tape a piece of
transfer
> paper over the artwork, and run it through the printer again, this
time
> printing onto the just-right sized piece of transfer paper.
Separate the
> three images.
>
> -- Print the drill guide and legend. Stick it to the board with
spray mount
> adhesive.
>
> -- Drill and debur the board. There are three unconnected vias in
the board
> corners for alignment pins.
>
> -- Pierce the alignment vias on the top artwork; place the pins in
the
> board; place the top artwork over the pins. Visually confirm
alignment, and
> tape in place. Black toner should occlude all holes.
>
> -- Remove the pins. Tear off a suitable size scrap of bond paper to
use as
> slip sheet. Fold in half; place the board with top artwork in the
crease.
> Run it through the laminator.
>
> -- Soak off the transfer paper. Pulsar's paper comes off cleanly in
a few
> seconds. Dry the board. Examine for alignment errors and incomplete
traces.
>
> -- Cut a piece of green sealer paper to size; laminate to the
exposed toner.
>
> -- Repeat for the bottom. The sealer prevents the completed top
artwork from
> sticking to the slip sheet.
>
> -- Etch.
>
> With one success for one try with the alignment pins, I'm ready to
try both
> sides at once. Pulsar's paper releases completely when wet and
makes it
> brain dead simple with a clean and deburred board. Slight hole
misalignments
> are entirely attributable to imprecise manual drilling. Since the
drill
> guide is printed on the same printer as the transferred artwork,
I'm not at
> all surprised to not find any systematic errors.
>
> Quality differences? It's difficult to see where the TT process can
be
> improved.
>